Sprint also overhauled its family pricing earlier this week. Under its new plans, a family with four phone lines would pay $160 per month to share 20GB of data.

Four lines with the same amount of data are advertised online by Verizon and AT&T at $310 per month. At T-Mobile, the plan would cost $180.

T-Mobile CEO on music, Amazon and Sprint

Sprint has also followed T-Mobile's lead in offering to reimburse customers for the costs of switching from other carriers, and waiving the requirement that customers sign a long-term service contract.

Sprint brought in Claure earlier this month to lead its turnaround effort after reportedly abandoning plans to merge with T-Mobile because of the difficulty in getting the deal approved by antitrust regulators. That merger would have created a combined entity with a subscriber count to rival that of Verizon and AT&T.

Claure, who formerly headed wireless equipment and service company Brightstar, pledged following his hiring to make Sprint more "aggressive in the marketplace," and he's wasted little time in following through.

But Sprint faces a difficult road ahead. Though its speeds are improving, it still has by far the slowest 4G network of its rivals. It was rated the worst cell phone service in the nation by Consumer Reports last year, and also came up in fourth in a new ranking this week from market research firm RootMetrics.

On top of all that, it continues to hemorrhage money and lose customers.